Implementation of Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF) and Antimicrobial Stewardship Intervention at an Academic Medical Center

Abstract

BackgroundRapid diagnostic tests (RDTs), such as Matrix-Assisted Laser Desorption/Ionization Time-of-Flight (MALDI-TOF), have been shown to improve time to effective therapy and positively impact patient outcomes when used along with antimicrobial stewardship team (AST) intervention in treating bloodstream infections (BSIs). The purpose of this study was to assess the impact of MALDI-TOF (implemented May 25, 2016) and AST intervention on management of BSIs at a smaller, resource-limited institution.MethodsIRB-approved, single-center, pre-post quasi-experiment including all patients treated for BSI at the University of Toledo Medical Center from November 1, 2015-November 30, 2016. Patients transferred with documented BSI, expired prior to organism identification, or had blood culture positive for Mycobacterium, Nocardia, anaerobes, or molds were excluded. Primary endpoint: time to effective therapy. Secondary endpoints: time to optimal therapy, hospital length of stay (LOS), recurrent bacteremia, and 30-day readmission and all-cause mortality.Results593 blood cultures screened, 261 included; 131 pre- and 130 post-MALDI-TOF implementation. Baseline characteristics similar between groups. Median (IQR) time to effective therapy was 6.1 h (2.3–20.0) pre-MALDI-TOF and 6.4 hours (2.2–23.7) post-MALDI-TOF, P = 0.609. Median (IQR) time to optimal therapy was 67.3 (48.6–93.2) pre-MALDI-TOF and 67.2 (44.3–94.0) post-MALDI-TOF, P = 0.520. Secondary endpoints shown in Table 1. In a subset of cultures defined as contaminants, reduction was seen in time to discontinuation of therapy, however not statistically significant (93.8 hours (61.8–131.4) vs. 71.1 hours (57.5–106.3); P = 0.180).ConclusionImplementation of MALDI-TOF and AST intervention did not significantly improve an already prompt time to effective therapy in patients with BSIs at our institution. Time to optimal therapy was also similar, highlighting the need for more rapid susceptibility tests in order to support earlier de-escalation of therapy.Table 1.Clinically Evaluable EndpointsPre-MALDI-TOF (n = 108)Post-MALDI-TOF (n = 104)P-valueHospital LOS (days)9.1 (6.2–15.6)10.0 (6.3–15.7)0.823Recurrent bacteremia6 (5.6)4 (3.8)0.74830-day readmission24 (22.2)18 (17.3)0.36930-day, all-cause mortality16 (14.8)19 (18.3)0.498Values reported as median (IQR) or n(%).Disclosures All authors: No reported disclosures.